The present invention relates to substituted 2H-naphtho[1,2-b]pyran compounds. More particularly, this invention relates to novel photochromic aromatic substituted naphthopyran compounds and to compositions and articles containing such novel naphthopyran compounds. When exposed to electromagnetic radiation containing ultraviolet rays, such as the ultraviolet radiation in sunlight or the light of a mercury lamp, many photochromic compounds exhibit a reversible change in color. When the ultraviolet radiation is discontinued, such a photochromic compound will return to its original color or colorless state.
Various classes of photochromic compounds have been synthesized and suggested for use in applications in which a sunlight-induced reversible color change or darkening is desired. U.S. Pat. No. 3,567,605 (Becker) describes a series of pyran derivatives, including certain benzopyrans and naphthopyrans. These compounds are described as derivatives of chromene and are reported to undergo a color change, e.g., from colorless to yellow-orange, on irradiation by ultraviolet light at temperatures below about xe2x88x9230xc2x0 C. Irradiation of the compounds with visible light or upon raising the temperature to above about 0xc2x0 C. is reported to reverse the coloration to a colorless state.
U.S. Pat. No. 5,066,818 describes various 3,3-diaryl-3H-naphtho[2,1-b]pyrans as having desirable photochromic properties, i.e., high colorability and acceptable fade, for ophthalmic and other applications. Also disclosed by way of comparative example in the ""818 patent are the isomeric 2,2-diaryl-2H-naphtho[1,2-b]pyrans, which are reported to require unacceptably long periods of time to fade after activation.
U.S. Pat. No. 3,627,690 describes photochromic 2,2-di-substituted-2H-naphtho[1,2-b]pyran compositions containing minor amounts of either a base or weak-to-moderate strength acid. The addition of either an acid or base to the naphthopyran composition is reported to increase the fade rate of the colored naphthopyrans, thereby making them useful in eye protection applications such as sunglasses. It is reported therein further that the fade rate of 2H-naphtho-[1,2-b]pyrans without the aforementioned additives ranges from several hours to many days to reach complete reversion.
U.S. Pat. No. 4,818,096 discloses purple/blue coloring photochromic benzo- or naphthopyrans having at the position alpha to the oxygen of the pyran ring a phenyl group having a nitrogen containing substituent in the ortho or para positions. U.S. Pat. No. 5,645,767 describes novel photochromic indeno-fused 2H-naphtho[1,2-b]pyran compounds, the 2,1-positions of the indeno group being fused to the f side of the naphthopyran.
The following four patents disclose related photochromic 2H-naphtho[1, 2-b]pyran compounds with certain substituents at the 2 position and certain aromatic substituents at the 5 position. U.S. Pat. No. 4,826,977 discloses naphthopyrans having an adamantane group at the 2 position, a phenyl or substituted phenyl group or a 5- or 6-membered heteroaromatic group at the 5 position. U.S. Pat. No. 4,931,221 discloses naphthopyrans having two cyclopropyl groups at the 2 position, and a phenyl or substituted phenyl group at the 5 position. U.S. Pat. No. 4,980,089 describes naphthopyrans having a norcamphor group or a tricyclodecane group at the 2 position, and a furyl group, thienyl group or phenyl or substituted phenyl group at the 5 position. U.S. Pat. No. 5,200,116 describes naphthopyrans having a cyclopropyl group along with a phenyl or substituted phenyl group, thienyl, benzothienyl group, or furyl or benzofuryl group at the 2 position and a phenyl or substituted phenyl group at the 5 position. The substituents of the 5 position phenyl groups disclosed in these four patents are C1-C4 alkyl, C1-C4 alkoxy, chloro or bromo.
U.S. Pat. No. 5,458,814 discloses photochromic 2H-naphtho[1,2-b]pyran compounds having certain substituents at the number 5 and 6 carbon atoms of the naphtho portion of the naphthopyran, and at the 2-position of the pyran ring. These compounds have an acceptable fade rate in addition to a high activated intensity and a high coloration rate.
The present invention relates to a naphthopyran of 2H-naphtho[1,2-b]pyran structure characterized by having and aromatic substituent in the 5 position. The compounds also have substituents at the 2 position of the pyran ring. The aromatic group at the 5-position of the naphthopyran is a substituted or unsubstituted phenyl or naphthyl group or other substituted or unsubstituted heteroaromatic group. It has unexpectedly been discovered that the compounds of the present invention are faster to fade than 2H-naphthopyrans having similar photochromic properties that are unsubstituted or have an aromatic substituent in the 5 position and a different substituent in the 6 position.
In recent years, photochromic plastic materials, particularly plastic materials for optical applications, have been the subject of considerable attention. In particular, photochromic ophthalmic plastic lenses have been investigated because of the weight advantage they offer, vis-à-vis, glass lenses. Moreover, photochromic transparencies for vehicles, such as cars and airplanes, have been of interest because of the potential safety features that such transparencies offer.
In accordance with the present invention, it has now been discovered that 2H-naphtho[1,2-b]pyrans characterized by having in the 5 position, a group xe2x80x94Ar(R2)n(COOR3)p, that produce an activated yellow-orange color may be prepared. These compounds may be described as naphthopyrans having at the number 5 carbon atom of the naphthopyran a substituted or unsubstituted phenyl or naphthyl group or another substituted or unsubstituted heteroaromatic substituent, and substituents at the 2 position of the pyran ring. Substituents may also be present at the number 7, 8, 9 or 10 carbon atoms of the naphthopyran compound. The number 6 carbon atom of the naphthopyran compound has a hydrogen substituent.
The foregoing described naphthopyran compounds may be represented by the following graphic formula I in which the numbers 1 through 10 identify the ring atoms of the naphthopyran. 
Ar in graphic formula I may be selected from the group consisting of:
(i) an aryl group consisting of phenyl and naphthyl; and
(ii) an aromatic group consisting of furanyl, benzofuran-2-yl, benzofuran-3-yl, thienyl, benzothien-2-yl, benzothien-3-yl, dibenzofuran-4-yl, and dibenzothien-4-yl. Preferably, Ar is phenyl or thienyl.
In graphic formula I, each R1 may be C1-C6 alkyl, C1-C6 alkoxy, or halogen, said halogen being bromo, chloro, fluoro or iodo and m is the integer 0, 1, 2 or 3. In one contemplated embodiment, each R1 is C1-C4 alkyl, C1-C4 alkoxy, chloro or fluoro, and m is the integer 0, 1 or 2. In another contemplated embodiment, each R1 is C1-C3 alkyl or C1-C3 alkoxy, and m is the integer 0 or 1.
Each R2 in graphic formula I may be selected from the group consisting of aryl, i.e., phenyl and naphthyl, mono(C1-C6)alkoxyaryl, di(C1-C6)alkoxyaryl, mono(C1-C6)alkylaryl, di(C1-C6)alkylaryl, haloaryl, C3-C7 cycloalkylaryl, C3-C7 cycloalkyl, C3-C7 cycloalkyloxy, C3-C7 cycloalkyloxy(C1-C6)alkyl, C3-C7 cycloalkyloxy(C1-C6)alkoxy, aryl(C1-C6)alkyl, aryl(C1-C6)alkoxy, aryloxy, aryloxy(C1-C6)alkyl, aryloxy(C1-C6)alkoxy, mono- and di(C1-C6)alkylaryl(C1-C6)alkyl, mono- and di(C1-C6)alkoxyaryl(C1-C6)alkyl, mono- and di(C1-C6)alkylaryl(C1-C6)alkoxy, mono- and di(C1-C6)alkoxyaryl(C1-C6)alkoxy, C1-C6 alkyl, C1-C6 bromoalkyl, C1-C6 chloroalkyl, C1-C6 fluoroalkyl, C1-C6 alkoxy, mono(C1-C6)alkoxy(C1-C4)alkyl, and halogen, said halogen being bromo, chloro, fluoro or iodo, and n is the integer 0, 1, 2, or 3. In one contemplated embodiment, each R2 is selected from the group consisting of aryl, aryloxy, aryl(C1-C3)alkyl, C1-C3 alkyl, C1-C3 chloroalkyl, C1-C3 fluoroalkyl, C1-C3 alkoxy, mono(C1-C3)alkoxy(C1-C3)alkyl, fluoro and chloro and n is the integer 0, 1 or 2. In another contemplated embodiment, each R2 is selected from the group consisting of C1-C3 alkyl, C1-C3 alkoxy, aryl, fluoro and chloro and n is the integer 0 or 1.
R3 in graphic formula I may be C1-C4 alkyl, phenyl, mono(C1-C4)alkyl substituted phenyl, mono(C1-C4)alkoxy substituted phenyl, phenyl(C1-C2)alkyl, mono(C1-C4)alkyl substituted phenyl(C1-C2)alkyl, mono(C1-C4)alkoxy substituted phenyl(C1-C2)alkyl, mono(C1-C4)alkoxy(C2-C3)alkyl, or C1-C4 haloalkyl, and p is the integer 0, 1 or 2, provided that the sum of n and p is less than or equal to 3 and when p is 2, n is 0. In one contemplated embodiment, R3 is C1-C3 alkyl and p is the integer 0 or 1. In another contemplated embodiment, the ester group containing R3 is ortho to the atom of the Ar group linked to the number 5 carbon atom of the naphtho portion of the naphthopyran.
B and Bxe2x80x2 in graphic formula I may each be selected from the group consisting of:
(i) an unsubstituted, mono-, di- and tri-substituted aryl group consisting of phenyl and naphthyl;
(ii) an unsubstituted, mono- and di-substituted heteroaromatic group consisting of pyridyl, furanyl, benzofuran-2-yl, benzofuran-3-yl, thienyl, benzothien-2-yl, benzothien-3-yl, dibenzofuran-4-yl, dibenzothien-4-yl, and carbazol-4-yl, each of said aryl and heteroaromatic substituents in parts (i) and (ii) being selected from the group consisting of hydroxy, aryl, mono(C1-C6)alkoxyaryl, di(C1-C6)alkoxyaryl, mono(C1-C6)alkylaryl, di(C1-C6)alkylaryl, haloaryl, C3-C7 cycloalkylaryl, C3-C7 cycloalkyl, C3-C7 cycloalkyloxy, C3-C7 cycloalkyloxy(C1-C6)alkyl, C3-C7 cycloalkyloxy(C1-C6)alkoxy, aryl(C1-C6)alkyl, aryl(C1-C6)alkoxy, aryloxy, aryloxy(C1-C6)alkyl, aryloxy(C1-C6)alkoxy, mono- and di(C1-C6)alkylaryl(C1-C6)alkyl, mono- and di(C1-C6)alkoxyaryl(C1-C6)alkyl, mono- and di(C1-C6)alkylaryl(C1-C6)alkoxy, mono- and di(C1-C6)alkoxyaryl(C1-C6)alkoxy, amino, mono(C1-C6)alkylamino, di(C1-C6)alkylamino, diarylamino, N-(C1-C6)alkylpiperazino, N-arylpiperazino, aziridino, indolino, piperidino, arylpiperidino, morpholino, thiomorpholino, tetrahydroquinolino, tetrahydroisoquinolino, pyrryl, C1-C6 alkyl, C1-C6 haloalkyl, C1-C6 alkoxy, mono(C1-C6)alkoxy(C1-C4)alkyl, acryloxy, methacryloxy and halogen, said halogen and halo being bromo, chloro, fluoro or iodo;
(iii) the group represented by graphic formula IIA or IIB: 
wherein E may be methylene or oxygen and D may be oxygen or substituted nitrogen, provided that when D is substituted nitrogen, E is methylene, said nitrogen substituents being selected from the group consisting of hydrogen, C1-C6 alkyl and C2-C6 acyl; each R4 is C1-C6 alkyl, C1-C6 alkoxy, hydroxy, or halogen, said halogen being bromo, chloro, fluoro or iodo; R5 and R6 are each hydrogen or C1-C6 alkyl; and q is the integer 0, 1 or 2;
(iv) C1-C6 alkyl, C1-C6 haloalkyl, C1-C6 alkoxy(C1-C4)alkyl; and
(v) the group represented by the following graphic formula: 
wherein X in graphic formula IIC may be hydrogen or C1-C4 alkyl and Z in graphic formula IIC may be selected from the unsubstituted, mono-, and di-substituted members of the group consisting of naphthyl, phenyl, furanyl and thienyl, each of said group substituents in this part (v) being C1-C4 alkyl, C1-C4 alkoxy, or halogen.
In one contemplated embodiment, B and Bxe2x80x2 are each selected from the group consisting of: (i) phenyl, mono-substituted phenyl and di-substituted phenyl, preferably substituted in the meta and/or para positions; (ii) the unsubstituted, mono- and di-substituted heteroaromatic groups furanyl, benzofuran-2-yl, thienyl, benzothien-2-yl, dibenzofuran-2-yl and dibenzothien-2-yl, each of said phenyl and heteroaromatic substituents in (i) and (ii) being selected from the group consisting of hydroxy, aryl, aryloxy, aryl(C1-C3)alkyl, amino, mono(C1-C3)alkylamino, di(C1-C3)alkylamino, N-(C1-C3)alkylpiperazino, indolino, piperidino, morpholino, pyrryl, C1-C3 alkyl, C1-C3 chloroalkyl, C1-C3 fluoroalkyl, C1-C3 alkoxy, mono(C1-C3)alkoxy(C1-C3)alkyl, fluoro and chloro; (iii) the groups represented by the graphic formulae IIA and IIB, wherein E is methylene and D is oxygen, R4 is C1-C3 alkyl or C1-C3 alkoxy, R5 and R6 are each hydrogen or C1-C4 alkyl; and q is the integer 0 or 1; (iv) C1-C4 alkyl; and (v) the group represented by the graphic formula IIC wherein X is hydrogen or methyl and Z is phenyl or mono-substituted phenyl, said phenyl substituent being selected from the group consisting of C1-C3 alkyl, C1-C3 alkoxy and fluoro.
In another contemplated embodiment, B and Bxe2x80x2 are each selected from the group consisting of (i) phenyl, mono-and di-substituted phenyl; (ii) the unsubstituted, mono- and di-substituted heteroaromatic groups furanyl, benzofuran-2-yl, thienyl and benzothien-2-yl, each of said phenyl and heteroaromatic substituents in (i) and (ii) being selected from the group consisting of hydroxy, C1-C3 alkyl, C1-C3 alkoxy, aryl, indolino, fluoro and chloro; and (iii) the group represented by graphic formula IIA, wherein E is carbon and D is oxygen, R4 is C1-C3 alkyl or C1-C3 alkoxy, R5 and R6 are each hydrogen or C1-C3 alkyl, and q is the integer 0 or 1.
Compounds represented by graphic formula I may be prepared by the following described Reactions A through D. Compounds represented by graphic formula V or VA are either purchased or prepared by Friedel-Crafts methods shown in Reaction A using an appropriately substituted or unsubstituted benzoyl chloride of graphic formula IV with a commercially available substituted or unsubstituted benzene compound of graphic formula III. See the publication Friedel-Crafts and Related Reactions, George A. Olah, Interscience Publishers, 1964, Vol. 3, Chapter XXXI (Aromatic Ketone Synthesis), and xe2x80x9cRegioselective Friedel-Crafts Acylation of 1,2,3,4-Tetrahydroquinoline and Related Nitrogen Heterocycles: Effect on NH Protective Groups and Ring Sizexe2x80x9d by Ishihara, Yugi et al, J. Chem. Soc., Perkin Trans. 1, pages 3401 to 3406, 1992.
In Reaction A, the compounds represented by graphic formulae III and IV are dissolved in a solvent, such as carbon disulfide or methylene chloride, and reacted in the presence of a Lewis acid, such as aluminum chloride or tin tetrachloride, to form the corresponding substituted benzophenone represented by graphic formula V (or VA in Reaction B). R and Rxe2x80x2 represent possible substituents, as described hereinbefore with respect to graphic formula I. 
In Reaction B, the substituted or unsubstituted ketone represented by graphic formula VA, in which B and Bxe2x80x2 may represent groups other than substituted or unsubstituted phenyl, as shown in graphic formula V, is reacted with sodium acetylide in a suitable solvent, such as anhydrous tetrahydrofuran (THF), to form the corresponding propargyl alcohol represented by graphic formula VI. Propargyl alcohols having B or Bxe2x80x2 groups other than substituted and unsubstituted phenyl may be prepared from commercially available ketones or ketones prepared via reaction of an acyl halide with a substituted or unsubstituted benzene, naphthalene or heteroaromatic compound. Propargyl alcohols having a B or Bxe2x80x2 group represented by graphic formula IIC may be prepared by the methods described in U.S. Pat. No. 5,274,132, column 2, lines 40 to 68.

In Reaction C, the compounds represented by graphic formulae VII and VIII are first reacted at elevated temperatures and then further reacted in the presence of a base such as potassium hydroxide to form the corresponding substituted naphthol represented by graphic formula IX. Compounds VII and VIII may each be purchased. Alternatively, compound VIII may be prepared by the method described by T. Sakamoto et al., Synthesis, pages 312-314 (1983) and by S. Takahashi et al., Synthesis, pages 627-630 (1980). Synthesis of phenyl naphthols are further described in C. Kipping et al., J. Pralet. Chem., Vol. 315, pages 887-894 (1973) and J. Bao et al., J. Amer. Chem. Soc., Vol. 118, pages 3392-3405 (1996).

In Reaction D, the propargyl alcohol represented by graphic formula VI is coupled with the naphthol represented by graphic formula IX in the presence of an acid such as p-toluene sulfonic acid (PTSA) and in a suitable solvent such as toluene to form compounds represented by graphic formula I.

Compounds represented by graphic formula I may be used in those applications in which organic photochromic substances may be employed, such as optical lenses, e.g., vision correcting ophthalmic lenses, contact lenses and plano lenses, face shields, goggles, visors, camera lenses, windows, automotive windshields, aircraft and automotive transparencies, e.g., T-roofs, sidelights and backlights, plastic films and sheets, textiles and coatings, e.g., coating compositions. As used herein, coating compositions are defined herein to include polymeric coating compositions prepared from materials such as polyurethanes, epoxy resins and other resins used to produce synthetic polymers; paints, i.e., a pigmented liquid or paste used for the decoration, protection and/or the identification of a substrate; and inks, i.e., a pigmented liquid or paste used for writing and printing on substrates Potential substrates for coating compositions containing the compounds of the present invention include paper, glass, ceramics, wood, masonry, textiles, metals and polymeric organic materials.
Coating compositions may be used to produce polymeric coatings on optical elements, verification marks on security documents, e.g., documents such as banknotes, passport and drivers"" licenses, for which authentication or verification of authenticity may be desired. The 5-aromatic substituted naphthopyrans represented by graphic formula I exhibit color changes from colorless to colors ranging from yellow to orange.
Examples of naphthopyrans and contemplated naphthopyran compounds that have or are expected to have desirable photochromic properties and are within the scope of the invention include the following:
(a) 2,2-diphenyl-5-(2-methoxycarbonylphenyl)-2H-naphtho[1, 2-b]pyran;
(b) 2,2-diphenyl-5-(4-methoxycarbonylphenyl)-2H-naphtho[1,2-b]pyran;
(c) 2,2-diphenyl-5-(thien-2-yl)-2H-naphtho[1,2-b]pyran;
(d) 2,2-diphenyl-5-(phenyl)-2H-naphtho[1,2-b]pyran;
(e) 2-phenyl, 2-(4-methoxyphenyl)-5-phenyl-2H-naphtho[1,2-b]pyran;
(f) 2,2-di(4-methoxyphenyl)-5-phenyl-2H-naphtho[1,2-b]pyran;
(g) 2-phenyl, 2-(4-morpholinophenyl)-5-phenyl-2H-naphtho[1,2-b]pyran;
(h) 2,2-di(4-methoxyphenyl)-9-methoxy-5-phenyl-2H-naphtho[1,2-b]pyran;
(i) 2-phenyl, 2-(4-morpholinophenyl)-9-methoxy-5-phenyl-2H- naphtho[1,2-b]pyran;
(j) 2,2-di(4-methoxyphenyl)-5-(4-methylphenyl)-2H-naphtho[1,2-b]pyran;
(k) 2-phenyl, 2-(4-methoxyphenyl)-5(4-methylphenyl)-2H-naphtho[1,2-b]pyran; and
(1) 2,2-di(4-methoxyphenyl)-9-methoxy-5-(4-methylphenyl)-2H-naphtho[1,2-b]pyran.
Other than where otherwise indicated, all numbers expressing wavelengths, quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term xe2x80x9caboutxe2x80x9d.
The disclosures of the patents and articles cited herein describing procedures for making the compounds of the present invention, complementary photochromic compounds, polymeric coatings and methods of applying such coatings, polymeric organic host materials and polymerizates are incorporated herein, in toto, by reference.
It is contemplated that the organic photochromic naphthopyrans of the present invention may be used alone, in combination with other naphthopyrans of the present invention, or in combination with one or more other appropriate complementary organic photochromic materials, i.e., organic photochromic compounds having at least one activated absorption maxima within the range of between about 400 and 700 nanometers, or substances containing same, and may be incorporated, e.g., dissolved or dispersed, in a polymeric organic host material used to prepare photochromic articles and which color when activated to an appropriate hue.
The complementary organic photochromic compounds may include other naphthopyrans, benzopyrans, indenonaphthopyrans, oxazines, phenanthropyrans, spiro(benzindoline)naphthopyrans, spiro(indoline)benzopyrans, spiro(indoline)naphthopyrans, spiro(indoline)quinopyrans, spiro(indoline)pyrans, spiro( indoline)naphthoxazines, spiro(indoline)pyridobenzoxazines, spiro(benzindoline)pyridobenzoxazines, spiro(benzindoline)naphthoxazines, spiro(indoline)benzoxazines, mercury dithizonates, fulgides, fulgimides and mixtures of such photochromic compounds. Many of such photochromic compounds are described in the open literature, e.g., U.S. Pat. Nos. 5,645,767 and 6,153,126.
Each of the photochromic substances described herein may be used in amounts (or in a ratio) such that an organic host material to which the photochromic compounds or mixture of compounds is applied or in which they are incorporated exhibits a desired resultant color, e.g., a substantially neutral color when activated with unfiltered sunlight, i.e., as near a neutral color as possible given the colors of the activated photochromic compounds. Neutral gray and neutral brown colors are preferred. Further discussion of neutral colors and ways to describe colors may be found in U.S. Pat. No. 5,645,767 column 12, line 66 to column 13, line 19.
The amount of photochromic substance or composition containing same applied to or incorporated into a coating composition or a host material is not critical provided that a sufficient amount is used to produce a photochromic effect discernible to the naked eye upon activation. Generally such amount can be described as a photochromic amount. The particular amount used depends often upon the intensity of color desired upon irradiation thereof and upon the method used to incorporate or apply the photochromic substances. Typically, the more photochromic substance applied or incorporated, the greater is the color intensity up to a certain limit.
The relative amounts of the aforesaid photochromic compounds used will vary and depend in part upon the relative intensities of the color of the activated species of such compounds, and the ultimate color desired. Generally, the amount of total photochromic substance incorporated into or applied to a photochromic optical host material may range from 0.05 to 2.0, e.g., from 0.2 to 1.0, milligrams per square centimeter of surface to which the photochromic substance(s) is incorporated or applied. The amount of photochromic material incorporated into a coating composition may range from 0.1 to 40 weight percent based on the weight of the liquid coating composition.
The photochromic naphthopyrans of the present invention may be associated with the host material by various methods described in the art. See, for example, column 13, lines 40 to 58 of U.S. Pat. No. 5,645,767. Aqueous or organic solutions or dispersions of the photochromic compounds may be used to incorporate the photochromic compounds into a polymeric organic host material or other materials such as textiles and coating compositions. Coating compositions may be applied to the substrate using a coating process such as that described in U.S. Pat. 3,971,872.
Application of the polymeric coating may be by any of the methods used in coating technology such as, for example, spray coating, spin coating, spread coating, curtain coating, dip coating, casting or roll-coating and methods used in preparing overlays, such as the method of the type described in U.S. Pat. No. 4,873,029. The application method selected also depends on the thickness of the cured coating. Coatings having a thickness ranging from 1 to 50 microns may be applied by conventional methods used in coating technology. Coatings of a thickness greater than 50 microns may require molding methods typically used for overlays.
The polymeric coating composition includes compositions resulting in thermoplastic or thermosetting coatings, which are described in the Kirk-Othmer Encyclopedia of Chemical Technology, Fourth Edition, Volume 6, pages 669 to 760. The coating may comprise at least one, polymer selected from the group consisting of polyurethanes, melamine resins, polyvinyl alcohol, polyacrylates, polymethacrylates, polyamide resins and epoxy resins. Such polymer-forming coating compositions are described in U.S. Pat. No. 4,425,403.
The host material will usually be transparent, but may be translucent or even opaque. The host material need only be pervious to that portion of the electromagnetic spectrum, which activates the photochromic substance, i.e., that wavelength of ultraviolet (UV) light that produces the open or colored form of the substance and that portion of the visible spectrum that includes the absorption maximum wavelength of the substance in its UV activated form, i.e., the open form. Preferably, the host color should not be such that it masks the color of the activated form of the photochromic compounds, i.e., so the change in color is readily apparent to the observer. Compatible tints may be applied to the host material as described in U.S. Pat. No. 5,645,767 in column 13, line 59 to column 14, line 3.
Most preferably, the polymeric organic host material is a solid transparent or optically clear material, e.g., materials suitable for optical applications, such as plano, ophthalmic and contact lenses, windows, automotive transparencies, e.g., windshields, aircraft transparencies, plastic sheeting, polymeric films, etc.
Examples of polymeric organic host materials which may be used with the photochromic compounds described herein include: polymers, i.e., homopolymers and copolymers, of the bis(allyl carbonate) monomers, diethylene glycol dimethacrylate monomers, diisopropenyl benzene monomers, ethoxylated bisphenol A dimethacrylate monomers, ethylene glycol bismethacrylate monomers, poly(ethylene glycol) bismethacrylate monomers, ethoxylated phenol bismethacrylate monomers, alkoxylated polyhydric alcohol acrylate monomers, such as ethoxylated trimethylol propane triacrylate monomers, urethane acrylate monomers, such as those described in U.S. Pat. No. 5,373,033, and vinylbenzene monomers, such as those described in U.S. Pat. No. 5,475,074 and styrene; polymers, i.e., homopolymers and copolymers, mono- or polyfunctional, e.g., di- or multi-functional, acrylate and/or methacrylate monomers, poly(C1-C12 alkyl methacrylates), such as poly(methyl methacrylate), poly(oxyalkylene)dimethacrylate, poly(alkoxylated phenol methacrylates), cellulose acetate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, poly(vinyl acetate), poly(vinyl alcohol), poly(vinyl chloride), poly(vinylidene chloride), polyurethanes, polythiourethanes, thermoplastic polycarbonates, polyesters, poly(ethylene terephthalate), polystyrene, poly(alpha methylstyrene), copoly(styrene-methyl methacrylate), copoly(styrene-acrylonitrile), polyvinylbutyral and polymers, i.e., homopolymers and copolymers, of diallylidene pentaerythritol, particularly copolymers with polyol (allyl carbonate) monomers, e.g., diethylene glycol bis(allyl carbonate), and acrylate monomers, e.g., ethyl acrylate, butyl acrylate. Further examples of polymeric organic host materials are disclosed in the U.S. Pat. No. 5,753,146, column 8, line 62 to column 10, line 34.
Transparent copolymers and blends of transparent polymers are also suitable as host materials. Preferably, the host material or substrate for the photochromic polymeric coating composition is an optically clear polymerized organic material prepared from a thermoplastic polycarbonate resin, such as the carbonate-linked resin derived from bisphenol A and phosgene, which is sold under the trademark, LEXAN; a polyester, such as the material sold under the trademark, MYLAR; a poly(methyl methacrylate), such as the material sold under the trademark, PLEXIGLAS; polymerizates of a polyol(allyl carbonate) monomer, especially diethylene glycol bis(allyl carbonate), which monomer is sold under the trademark CR-39, and polymerizates of copolymers of a polyol (allyl carbonate), e.g., diethylene glycol bis(allyl carbonate), with other copolymerizable monomeric materials, such as copolymers with vinyl acetate, e.g., copolymers of from 80-90 percent diethylene glycol bis(allyl carbonate) and 10-20 percent vinyl acetate, particularly 80-85 percent of the bis(allyl carbonate) and 15-20 percent vinyl acetate, and copolymers with a polyurethane having terminal diacrylate functionality, as described in U.S. Pat. Nos. 4,360,653 and 4,994,208; and copolymers with aliphatic urethanes, the terminal portion of which contain allyl or acrylyl functional groups, as described in U.S. Pat. No. 5,200,483; poly(vinyl acetate), polyvinylbutyral, polyurethane, polythiourethanes, polymers of members of the group consisting of diethylene glycol dimethacrylate monomers, diisopropenyl benzene monomers, ethoxylated bisphenol A dimethacrylate monomers, ethylene glycol bismethacrylate monomers, poly(ethylene glycol) bismethacrylate monomers, ethoxylated phenol bismethacrylate monomers and ethoxylated trimethylol propane triacrylate monomers; cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, polystyrene and copolymers of styrene with methyl methacrylate, vinyl acetate and acrylonitrile.
More particularly contemplated is use of the photochromic naphthopyrans of the present invention with optical organic resin monomers used to produce optically clear coatings and polymerizates, i.e., materials suitable for optical applications, such as for example plano and ophthalmic lenses, windows, and automotive transparencies. Such optically clear polymerizates may have a refractive index that may range from 1.48 to 1.75, e.g., from 1.495 to 1.66.
Specifically contemplated are polymerizates of optical resins sold by PPG Industries, Inc. under the CR-designation, e.g., CR-307, CR-407 and CR-607, and polymerizates prepared for use as hard or soft contact lenses. Methods for producing both types of contact lenses are disclosed in U.S. Pat. No. 5,166,345, column 11, line 52, to column 12, line 52. Additional polymerizates contemplated for use with the photochromic naphthopyrans of the present invention are polymerizates used to form soft contact lenses with high moisture content described in U.S. Pat. No. 5,965,630 and extended wear contact lenses described in U.S. Pat. No. 5,965,631.